In recent years, head-mounted display (“HMD”) technology has increased in popularity with applications in virtual and augmented reality. An HMD is a display device worn on a user's head typically in the form of eyeglasses, goggles, a helmet, or a visor. The display device may be a single small electronic display unit positioned in the field of view of one eye of the user when the HMD is worn by the user, or the display device may be implemented with two separate small electronic display units positioned in the field of views of both eyes of the user when the HMD is worn by the user. For example, the small electronic display units may be implemented using either a small plasma display panel or a liquid crystal display. A small display unit used in an HMD may also be implemented with one or more lenses, collimating reflectors, and semi-transparent mirrors that focus the image created with the display panel. An HMD may use one display unit to create an augmented reality viewing experience, or an HMD may be implemented with two display units to create a virtual reality viewing experience.
Certain examples and embodiments may have other features that are one of in addition to and in lieu of the features illustrated in the above-referenced figures. These and other features are described below with reference to the above-referenced figures.